Dengue virus (DENV) is the most prevalent arthropod-borne virus worldwide and an emerging global health threat. There is no vaccine for preventing DENV infection and no anti-viral drugs for treating dengue-related disease. Currently, the only method of preventing DENV infection in humans is preventing exposure to mosquito vectors that transmit the virus. Replication of DENV is dependent on factors provided by the host cell. The identification of DENV host factors and elucidation of the molecular mechanisms by which the virus exploits these factors to promote its own replication are critical steps in identifying candidate targets for anti- viral molecules. The goal of this proposal is to identify interactions between cellular RNA-binding proteins (RBP) and DENV RNA and to characterize the role of these interactions in regulating DENV replication in both human and mosquito cells. Using a combination of biochemical and genetic approaches, we propose to elucidate the mechanism by which DENV appropriates the function of the cellular RBP polypyrimidine-tract binding protein (PTB) to augment virus replication. We will also use an innovative approach to identify novel interactions between cellular RBP and DENV RNA in infected human and mosquito cells. This work will significantly advance the field of DENV biology by not only informing our understanding of the molecular mechanisms of DENV replication but also by revealing potential candidate targets for anti-viral compounds.